Evaluating the effectiveness of high thermal resistance aggregates in asphalt mixtures for Urban Heat Island (UHI) mitigation

This study investigates how different asphalt mixtures can mitigate the Urban Heat Island (UHI) effect by analysing their thermal properties, including conductivity, heat storage, and thermal inertia. Limestone asphalt mixtures (LM), characterised by high thermal inertia, were compared with glass (GM), ceramic (CM), and clay brick (CBM) mixtures, which have lower thermal inertia. Laboratory and field tests conducted during the summers of 2022 and 2023 evaluated how these materials respond to solar radiation and ambient conditions. LM exhibited more stable surface temperatures due to slower heating and cooling, whereas GM, CM, and CBM cooled more quickly at night, which helped reduce heat accumulation and UHI intensity. The research highlights the novel use of recycled materials—glass, ceramic, and brick—in asphalt mixtures and emphasises the importance of optimising air voids to enhance thermal performance. These findings support the development of sustainable asphalt designs that promote daytime heat dissipation and nighttime cooling in urban areas.